Processing facilities are often managed using process control systems. Example processing facilities include manufacturing plants, chemical plants, crude oil refineries, and ore processing plants. Among other operations, process control systems typically manage the use of motors, valves, and other industrial equipment in the processing facilities.
In conventional process control systems, controllers are often used to control the operation of the industrial equipment in the processing facilities. The controllers could, for example, monitor the operation of the industrial equipment, provide control signals to the industrial equipment, and generate alarms when malfunctions are detected.
In recent years, more advanced and complex controllers, such as multivariable controllers, have been introduced and used in process control systems. These more advanced controllers are often useful in coping with various trends in the process control industry, such as tighter product specifications, improved quality, and reduced waste. However, the performance of these controllers often degrades over time due to process or other changes. As a result, it is often desirable to engage in controller performance monitoring, where the performance of a controller is monitored to determine if and when the controller requires maintenance (such as re-tuning). Unfortunately, controller performance monitoring is often a difficult task due to various reasons, such as disturbances and noise in the processes being monitored and controlled.